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A 240° phase voltage clamped inverter is proposed for electric drives to extend motor speed and power ranges even at low traction battery voltage, reduce inverter power loss, eliminate the challenge of dc bus voltage tracking a desired $6{f}$ -frequency voltage waveform even if the motor speed is high (e.g., motor ${f} > $ 1000 Hz), and eliminate power inductors and HF transformers and use less additional power devices while achieving voltage boost. The 240° phase voltage clamped control is proposed for the case of motor phase voltage amplitude higher than Vb/ $\sqrt {3}$ (Vb is the battery voltage); if there is no voltage boost needed, the inverter operates in SVPWM or six step mode. The proposed inverter has no switching for two-thirds of switches, so power loss has a significant reduction. The inverter output voltage has a low CMV. Simulation results verify the proposed 240° phase voltage clamped inverter and control method. The inverter performance evaluation shows higher efficiency of the proposed inverter compared with the traditional 2-level inverter.

In this paper, a novel variable-voltage, variable-frequency, dual, three-level, quasi-Z-source, indirect matrix converter topology is proposed, including a detailed description of a modulation method and a control strategy for three-phase motors with open-ended windings. The proposed power drive system (PDS) supports bidirectional power flow and has a combined control of DC-link voltage and output AC voltage frequency. Experimentally validation was performed on a 4-kW PDS. For a given supply voltage amplitude and the same power switch voltage rating in the DC/AC converter, the proposed PDS can double the voltage output gain, thus being an interesting solution for high-power applications with motors designed for higher voltages. The proposed PDS topology, modulation method and motor control strategy can reduce the common-mode component, low-order harmonic content, peak values and dv/dt of the motor phase voltage, ultimately leading to lower winding insulation voltage stress at low-speed, low-voltage operation, lower harmonic losses in the motor, and ride-through capability over voltage sags in the mains, which are important advantages.

This paper proposes a novel four-quadrant vector controlled induction motor (IM) adjustable speed drive (ASD) system based on a recently proposed matrix converter topology called quasi-Z-source direct matrix converter (QZSDMC). The QZSDMC is formed by cascading the quasi-Z-source impedance network and the conventional direct matrix converter (DMC). The QZSDMC can provide buck-boost operation with voltage transfer ratio controlled by controlling the shoot-through duty ratio and bidirectional operation capability. The control strategy, which is based on the indirect field oriented control algorithm, is able to control the motor speed from zero to the rated value under full load condition during motoring and regenerating operation modes. The operating principle of the proposed system is presented in detail. The simulation and the real-time implementation results, using dSPACE 1103 ControlDesk, validate the high performance of the proposed four-quadrants IM-ASD based on QZSDMC system. The proposed four-quadrant vector controlled IM-ASD system based on the QZSDMC topology overcomes the voltage gain limitation of the traditional DMC and achieves buck and boost condition in four-quadrant modes with reduced number of switches, therefore achieving low cost, high efficiency, and reliability, compared with back-to-back converter.

Applications of switched reluctance motor (SRM) to direct drive robot are increasingly popular because of its valuable advantages. However, the greatest potential defect is its torque ripple owing to the significant nonlinearities. In this paper, a fuzzy neural network (FNN) is applied to control the SRM torque at the goal of the torque-ripple minimization. The desired current provided by FNN model compensates the nonlinearities and uncertainties of SRM. On the basis of FNN-based current closed-loop system, the trajectory tracking controller is designed by using the dynamic model of the manipulator, where the torque control method cancels the nonlinearities and cross-coupling terms. A single link robot manipulator directly driven by a four-phase 8/6-pole SRM operates in a sinusoidal trajectory tracking rotation. The simulated results verify the proposed control method and a fast convergence that the robot manipulator follows the desired trajectory in a 0.9-s time interval.